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111.
Arthur L. Ruoff 《高压研究》2013,33(5-6):639-645
Abstract We have now taken two materials (W, Mo) to pressures greater than the pressure at the center of the earth for the first time, with all pressures based on x-ray diffraction and shock-based equations of state. The present paper describes x-ray diffraction studies of a sample in which pressure equals or exceeds 438 GPa. It is noted that as a result of the process of pressure strengthening, pressures of 1 TPa may be attainable. Presented at the IUCr Workshop on ‘Synchrotron Radiation Instrumenration for HighPressure Crystallography’. Daresbury Laboratory 20-21 July 1991 相似文献
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We continue the study of tall cardinals and related notions begun by Hamkins in 2009 and answer three of his questions posed in that paper. 相似文献
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Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular. 相似文献
115.
Saidbakhrom Saidjalolov Dr. Zainab Edoo Dr. Matthieu Fonvielle Louis Mayer Dr. Laura Iannazzo Dr. Michel Arthur Prof. Dr. Mélanie Etheve-Quelquejeu Dr. Emmanuelle Braud 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(10):3542-3551
The carbapenem class of β-lactams has been optimized against Gram-negative bacteria producing extended-spectrum β-lactamases by introducing substituents at position C2. Carbapenems are currently investigated for the treatment of tuberculosis as these drugs are potent covalent inhibitors of l,d -transpeptidases involved in mycobacterial cell wall assembly. The optimization of carbapenems for inactivation of these unusual targets is sought herein by exploiting the nucleophilicity of the C8 hydroxyl group to introduce chemical diversity. As β-lactams are structure analogs of peptidoglycan precursors, the substituents were chosen to increase similarity between the drug and the substrate. Fourteen peptido-carbapenems were efficiently synthesized. They were more effective than the reference drug, meropenem, owing to the positive impact of a phenethylthio substituent introduced at position C2 but the peptidomimetics added at position C8 did not further improve the activity. Thus, position C8 can be modified to modulate the pharmacokinetic properties of highly efficient carbapenems. 相似文献
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Grigor’ev Arthur A. Kayukov Yakov S. Nikiforova Anastasiya L. Karpov Sergey V. Shchegravina Ekaterina S. Kayukova Olga V. Tafeenko Victor A. 《Chemistry of Heterocyclic Compounds》2019,55(2):167-171
Chemistry of Heterocyclic Compounds - 4-Acyl-2-amino-6-chloropyridine-3,5-dicarbonitriles underwent heterocyclization in the presence of ammonia in aqueous dioxane medium, involving the... 相似文献
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A tunable microwave-assisted protocol for the synthesis of two biologically relevant families of heterocycles has been designed. Via a simple switch of reaction conditions, the same starting materials can be engaged in either an improved synthesis of the dihydrotriazine scaffold or a novel, first-in-class MCR to render the challenging 5-aminoimidazole nucleus in a single step. An additional first-in-class MCR is also reported utilizing guanidines to afford 2,5-aminoimidazoles. 相似文献
120.
Arthur R. Tulyabaev Airat R. Tuktarov Leonard M. Khalilov 《Magnetic resonance in chemistry : MRC》2014,52(1-2):3-9
Using gauge‐invariant atomic orbital PBE/3ζ quantum chemistry approach, 13C NMR chemical shifts and diastereotopic splittings of sp2 fullerenyl carbons of a number of sulfur homofullerenes and methanofullerenes have been predicted and discussed. An anisochrony of fullerene carbons is caused by a chiral center of attached moieties. Clearly distinguishable diastereotopic pairs (from 8 to 11) of fullerenyl carbons of homofullerenes were observed. Unambiguous assignments of 13C NMR chemical shifts were performed, and diastereotopic splittings of methanofullerenes were observed for α, β and γ to a functionalization site. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献